This application is a reissue of U.S. Pat. No. 5,521,720, which issued from application Ser. No. 08/248,092.
1. Field of the Invention
Present invention relates to an image processing apparatus having a plurality of resolutions.
2. Description of Related Art
Conventional image processing apparatuses, having a function for rotating information stored in a memory by a right angle (hereinafter referred to as xe2x80x9c90xc2x0 rotation functionxe2x80x9d), read an image in a mode specified from an operation unit and store the read image data into the memory. Such reading modes are usually called xe2x80x9cnormal modexe2x80x9d, xe2x80x9cfine modexe2x80x9d and xe2x80x9csuper-fine modexe2x80x9d. The resolution of the normal mode is 8 pel/mmxc3x973.85 line/mm; that of the fine mode, 8 pel/mmxc3x977.7 line/mm; and that of the super-fine mode, 8 pel/mmxc3x9715.41 line/mm (pel/mm: density in main-scanning direction; line/mm: density in subscanning direction).
When the conventional apparatus reads an image in the normal mode, it stores the read image data having 8 pel/mmxc3x973.85 line/mm resolution into a memory. The problem is that if a 90xc2x0 rotation is performed on the stored image data, the line density of the rotated data in the main-scanning direction is degraded to 3.85 pel/mm. The conventional art converts the degraded line density into 8 pel/mm so as to raise the resolution, however, deterioration of image quality cannot be avoided.
The present invention has been made in consideration of the above situation, and has as its object to provide an image processing apparatus capable of preventing deterioration of image quality.
It is another object of the present invention to provide an image processing apparatus capable of efficiently utilizing an image memory.
According to the present invention, the forgoing objects are attained by providing an image processing apparatus comprising: specifying means for specifying a resolution with respect to a direction defined on an image; input means for inputting the image at a predetermined resolution regardless of the resolution specified by said specifying means; rotation means for rotating the image inputted by said input means by a predetermined angle from the direction; and conversion means for converting a resolution in a resultant direction from rotating the image by said rotation means through the predetermined angle, in accordance with the resolution specified by said specifying means.
Other features and advantages of the present invention will be apparent from the following description taken in conjunction with the accompanying drawings, in which like reference characters designate the same or similar parts throughout the figures thereof.